A 3D games machine configured as shown in FIG. 19 is known as a prior art example of a 3D games machine that synthesizes a pseudo-3D image. This 3D games machine is configured of a control unit 510, a game space calculation unit 500, an image synthesizing unit 512, and a CRT 518, as shown in this figure. In this case, the purpose of the game space calculation unit 500 is to set a game space formed within a virtual 3D space, and is configured of a processing unit 502, a game space setting unit 504, and an image information storage unit 506. The purpose of the image synthesizing unit 512 is to form a pseudo-3D image as actually seen by a player, in accordance with settings from the game space setting unit 504, and is configured of an image supply unit 514 and an image rendering unit 516.
The operation of this prior-art example will now be described. Operating signals from the player are input to the game space calculation unit 500 through the control unit 510. An example of a game space formed within a virtual 3D space by this 3D games machine is shown in FIG. 20A. The game space calculation unit 500 places 3D objects such as a ground surface 519, mountains 520, a building 522, an installation 524, enemy aircraft 532, and the player's own aircraft 530 on a game field 540 according to operating signals and a previously stored game program, as shown in, for example, FIG. 20A.
Control of the entire 3D games machine is performed by the processing unit 502. Actual image information on the 3D objects, such as the ground surface 519, the mountains 520, the building 522, the installation 524, and the enemy aircraft 532, is stored in the image information storage unit 506. In this case, image information in which each of the 3D objects is divided into polygons and is rendered as such is stored in the image information storage unit 506, where this image information consists of polygon vertex information and auxiliary data.
The game space setting unit 504 places these 3D display objects within a virtual 3D space in accordance with operating signals from the player, the games program, and control signals from the processing unit 502. More specifically, the game space setting unit 504 adds the image information read out from the image information storage unit 506 with data that determines the positions and orientations of this image information, then outputs them to the image supply unit 514.
The image supply unit 514 performs processing such as transforming the coordinates of the thus-input data from an absolute coordinate system to a viewpoint coordinate system, clipping processing to exclude data that is outside the visual field, perspective projection conversion to a screen coordinate system, and sorting, then outputs the thus-processed data to the image rendering unit 516.
The image rendering unit 516 renders the image information that is to be seen by the player in practice, from the thus-input data. That is, since the data input from the image supply unit 514 consists of image information formed of data such as polygon vertex information, the image rendering unit 516 renders image information within these polygons from this polygon vertex information. After being processed, these data are output to the CRT 518 where they are rendered as a virtual 3D image as shown in FIG. 20B.
With the above described prior-art example, the image information consists of 3D objects represented simply by polygons, these 3D objects are all placed within a virtual 3D space, and thus a pseudo-3D image as seen from the player is rendered. The method of this prior-art example has advantages in that both the data processing flow and the previously prepared data are simple. However, it has a disadvantage in that, since the 3D objects are all rendered at the same level of resolution and also the processing places them all within the virtual 3D space, the amount of data to be processed becomes huge. This means that hardware limitations make it difficult to provide an image display in real time, resulting in problems such as extremely sluggish movement of the player's viewpoint, skip of the display of pictures as if they were separate photographs, and the failure of many objects to be displayed. The 3D games machine of this prior-art example has thus been unable to overcome the technical problems involved in producing a high-quality image display in real time.
This invention is intended to surmount the above technical problems, and has as an objective thereof the provision of a 3D games machine that can form a high-quality pseudo-3D image in real time.